Andy Lewis performed a slacklining routine during the Super Bowl halftime show, and amazed the audience. If slacklining is new to you, you can find out all about this extreme sport (or is it an art?) in an interview with climbing legend Dean Potter at National Geographic News Watch. Oh, yeah, that's him in the picture, at Yosemite Falls. See a video of Potter's trip across the abyss at NatGeo. Link-Thanks, Marilyn Terrell!